* GNU tools are often bloated, with extensions that the vast majority of people do not need or want. While we don't have quite the same focus on "must be small binary size" as Alpine, needless waste is still needless waste.

* GNU tools use gnulib, which is frequently incompatible with musl, and is a moving target for both building packages and passing tests. The number of patches I've personally had to write to make gnulib-based software work at all is dizzying.

* GNU projects have a lot of odd contribution hurdles: I've still never managed to connect with GRUB maintainers despite trying the Savannah page and the mailing lists. It was a chore to upstream other things.

Ease of understanding, perhaps. I found musl source code much easier to understand than GNU libc.

Or maybe GNU just rubs people the wrong way?